1. The Field of the Invention
The present invention relates to endodontics devices, more particularly to a device and method for easily determining whether moisture and/or aqueous sodium hypochlorite is present within the root canal of a tooth prior to sealing the root canal.
2. The Relevant Technology
When a dental practitioner performs a root canal, pulp and other material in the root canal chamber is removed. This is typically performed using one or more abrading endodontic files. Soft pulp material can be further broken up, disinfected and washed out using aqueous sodium hypochlorite. The sodium hypochlorite and any remaining debris can by flushed out by irrigating with water.
Once a dentist has removed diseased and soft tissue from a tooth's root canal, the chamber is typically filled. Before the canal can be filled with gutta percha, sealant or other suitable material, any moisture present within the canal is advantageously removed. It is beneficial to remove the moisture, which can otherwise result in bacterial infection of the chamber. Moisture can also inhibit bonding between the root canal walls and a sealant, if used. In some instances, pressurized air has been used to dry the canal, but because the source of pressurized air often contains moisture that can condense in the canal, use of this method has been discouraged. Dental practitioners have attempted to dry the canal by using cotton swabs or paper points which can be inserted down into the canal. Because of the relatively large size of cotton swabs and the narrow cross sections of the canals, especially in the apical region, complete removal of all moisture may prove difficult. Paper points are more easily inserted into the canal and are especially useful as they are able to extend through curved and narrow portions of the canal. Nevertheless, it may be difficult to determine whether all the moisture has been removed from the canal by visual inspection alone. One way to determine whether there is moisture in the root canal is to cause a paper point to change color in the presence of moisture. U.S. Pat. No. 6,482,009 to Rubin discloses an implement that includes a tip treated with a pH indicator. The problem with color changing pH indicators is that this typically only changes color within a specific working range of the pH scale. When a pH indicator is exposed to a pH outside the working range for that pH indicator, little or no color change may occur. Thus, the device of Rubin cannot guarantee a substantial color change, even if water is present, unless the pH in the root canal also happens to be within the applicable pH range of the indicator. Moreover, if there is sodium hypochlorite present in the root canal, the indicator of Rubin may never change color if it is entirely bleached away, providing a false negative.
A more reliable way to detect both moisture and sodium hypochlorite is provided in U.S. Publication No. 2005/0112528 to Wagner et al. In this application, a cobalt salt is provided that changes to one definitive color when exposed to moisture, regardless of pH, and to a different color when exposed to sodium hypochlorite. However, cobalt salts are disfavored in some places, including Europe, where they are believed to be carcinogenic or otherwise unhealthful. For this reason, warnings must typically be applied to products containing cobalt salts that are to be introduced into the mouth.
In view of the foregoing, it would be an improvement in the art to provide a device and method which may be used to safely and accurately determine and distinguish between whether moisture or aqueous sodium hypochlorite is present within a root canal.